juneau-core/juneau-marshall/src/main/java/org/apache/juneau/internal/Flag.java

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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.internal;

import static org.apache.juneau.common.internal.ThrowableUtils.*;

import org.apache.juneau.common.utils.*;

/**
 * A simple settable boolean value.
 */
public final class Flag {

	private boolean value;

	/**
	 * Creates a boolean value initialized to <jk>false</jk>.
	 *
	 * @return A new boolean value.
	 */
	public static Flag create() {
		return of(false);
	}

	/**
	 * Creates a boolean value with the specified initial state.
	 *
	 * @param value The initial state of the value.
	 * @return A new boolean value.
	 */
	public static Flag of(boolean value) {
		return new Flag(value);
	}

	private Flag(boolean value) {
		this.value = value;
	}

	/**
	 * Runs a snippet of code if the boolean value is <jk>true</jk>.
	 *
	 * <h5 class='section'>Example:</h5>
	 * <p class='bcode'>
	 * 	BoolValue <jv>flag</jv> = BoolValue.<jsm>create</jsm>();
	 * 	...
	 * 	<jv>flag</jv>.ifSet(()-&gt;<jsm>doSomething</jsm>());
	 * </p>
	 *
	 * @param snippet The snippet of code to run.
	 * @return This object.
	 */
	public Flag ifSet(Snippet snippet) {
		if (value)
			runSnippet(snippet);
		return this;
	}

	/**
	 * Runs a snippet of code if the boolean value is <jk>false</jk>.
	 *
	 * <h5 class='section'>Example:</h5>
	 * <p class='bcode'>
	 * 	BoolValue <jv>flag</jv> = BoolValue.<jsm>create</jsm>();
	 * 	...
	 * 	<jv>flag</jv>.ifNotSet(()-&gt;<jsm>doSomething</jsm>());
	 * </p>
	 *
	 * @param snippet The snippet of code to run.
	 * @return This object.
	 */
	public Flag ifNotSet(Snippet snippet) {
		if (! value)
			runSnippet(snippet);
		return this;
	}

	private void runSnippet(Snippet snippet) {
		try {
			snippet.run();
		} catch (Error | RuntimeException e) {
			throw e;
		} catch (Throwable e) {
			throw asRuntimeException(e);
		}
	}

	/**
	 * Sets the boolean value to <jk>true</jk> and returns the value before it was set.
	 *
	 * @return The previous value.
	 */
	public boolean getAndSet() {
		boolean b = value;
		value = true;
		return b;
	}

	/**
	 * Sets the boolean value to <jk>false</jk> and returns the value before it was set.
	 *
	 * @return The previous value.
	 */
	public boolean getAndUnset() {
		boolean v = value;
		value = false;
		return v;
	}

	/**
	 * Sets the boolean value to <jk>true</jk>.
	 *
	 * @return This object.
	 */
	public Flag set() {
		value = true;
		return this;
	}

	/**
	 * Sets the boolean value to <jk>false</jk>.
	 *
	 * @return This object.
	 */
	public Flag unset() {
		value = false;
		return this;
	}

	/**
	 * Returns <jk>true</jk> if the boolean value is <jk>true</jk>.
	 *
	 * @return <jk>true</jk> if the boolean value is <jk>true</jk>.
	 */
	public boolean isSet() {
		return value;
	}

	/**
	 * Returns <jk>true</jk> if the boolean value is <jk>false</jk>.
	 *
	 * @return <jk>true</jk> if the boolean value is <jk>false</jk>.
	 */
	public boolean isUnset() {
		return ! value;
	}

	/**
	 * Sets the boolean value to <jk>true</jk> if the value is <jk>true</jk>.
	 *
	 * @param value The value to set.
	 * @return This object.
	 */
	public Flag setIf(boolean value) {
		this.value |= value;
		return this;
	}
}